Magnetic proximity switches, also known as limit switches, are commonly used for linear position sensing. Generally, magnetic proximity switches typically include a target and a sensor. The sensor is coupled to a switching circuit having two leaf portions, a stationary portion and a movable portion hermetically sealed within a glass enclosure contained within a switch body. When the target passes within a predetermined range of the sensor, the magnetic flux generated by the target magnet causes the movable leaf to contact the stationary leaf, thereby closing the switch.
FIG. 1 depicts a conventional proximity switch 10 disposed within a switch box 12 operatively coupled to a rotary actuator 14 having a shaft 16. The switch box 12 includes an opening through which the shaft 16 passes. The switch box 12 houses both the conventional proximity switch 10 and a target carrier 18 having two target magnets 20 disposed thereon. The target carrier 18 also includes an opening for receiving the shaft 16, such that when the shaft 16 is rotated the target carrier 18 is rotated. To set the proximity switch 10 to trigger at a certain point of rotation of the actuator 14, the actuator 14, and, thus, the shaft 16, is rotated to that desired point. The proximity switch 10 is stationary; it never moves even when the shaft 16 moves.
However, as the actuator 14 is moved to set the angle of rotation at which the proximity switch 10 will be triggered, the shaft 16 moves and the target carrier 18 rotates. The target magnets 20 disposed thereon move to a non-calibrated position or a position that is not aligned with the proximity switch 10. As a result, a user must manually open the lid (not shown) of the switch box 12 to manually move the target magnets 20 back into alignment with the proximity switch 10. In other words, after the actuator 14 is rotated to a desired point at which the proximity switch 10 is to be triggered, one must physically set the proximity switch 10 to that point by moving the target magnets 20 back into alignment with the proximity switch 10, e.g., “zeroing” the proximity switch 10.
Thus, each time it is desired to change the angle at which the conventional proximity switch 10, such as a GoSwitch™, will be triggered, e.g., from 45° to 90° to 180° from the longitudinal axis of the shaft 16, a user must open a lid (not shown) of the switch box 12 to physically manipulate the system. This can cause valuable time loss to users, as certain operations may have to be halted while the switch box 12 is being worked on due to the switch box 12 being open, for example.